Complex automated manufacturing facilities employ a large number of individual processing components including robotic devices, sensors, environmental controls, pneumatic valves and other electronic input/output devices. Devices for the fabrication of semiconductor microcircuit wafers, in particular, require a rather complex web of electronic input and output signals to be passed between the master control computer and a myriad of remote sensors and process components. These signals, for example, control the movement of semiconductor wafers into and out of process chambers, control a multiplicity of valves that regulate process gasses and vacuum pressures, monitor and control process temperature, operate several electromechanical and pneumatic robot manipulators, regulate power supplies, monitor safety levels and transmit warnings and a variety of other important tasks in the semiconductor fabrication facility.
Users of semiconductor fabrication equipment in the US and abroad have unique process requirements that vary greatly based upon the country and individual users. There may be differing process parameter requirements, differing power supply needs, specific environmental and safety regulations that must be observed, and even different spoken language requirements. Makers of fabrication facilities have been forced to spend substantial time and resources meeting the specific needs of their purchasers, providing highly customized control systems that are, essentially, one-user units, and that are not readily adaptable to other users' with differing needs.
The customized nature of fabricating facilities is amplified by organizational structure of most control systems. Generally, control systems comprise a number of control cables routed directly to the master computer, sometimes with intervening control cards that perform minor data handling functions. However, the bulk of input/output ("I/O" herein) operations are performed directly by the master control computer, which is typically composed of one or more high performance microcomputers. Signals entering and exiting the master control computer are often organized in blocks or sectors without regard to the physical arrangement of processing components in the fabrication facility. In other words, the signals for several discrete components such as a manipulator arm, a vacuum assembly and a gas box may be lumped together into blocks within the computer's control procedure. Instead of using all signals for each physical component as the basis for signal organization, the signal blocks are often organized based upon related characteristics shared by several components, such as pneumatic pressure, temperature or mass flow rate. A plurality of corresponding "motherboards" may be provided between the control computer's I/O port(s) to provide appropriate data acquisition and communication interfaces. Typically, a widely dispersed labyrinth of wires and connecting cables is threaded throughout the facility to link I/O from the various components to their respective mother boards. Because of the large number of signals, and their interdependency based upon this organizational structure, it is extremely difficult to alter one component's I/O arrangement without effecting virtually every part of the control procedure. Hence, the initial set-up of a fabrication facility for a customer, and the subsequent modification of the facility require many hours of complicated programming by highly trained personnel. Even changing the language in which text is displayed by the facility's monitor can be a daunting task.
Additionally, the present control system does not lend itself to the addition or substitution of other maker's components easily, owing to the highly proprietary nature of the physical I/O links (wire arrangement) and communication protocol (signal characteristics) between process components and the master control computer. This can limit a fabrication facility's versatility.
Finally, the present arrangement of control system hardware requires substantial floor space since several data processing devices are often employed. A variety of differing types of interfaces are also interposed about the facility. This arrangement takes up manufacturing floor space that is especially expensive in the semiconductor fabrication industry in which valuable clean room resources are required.
It is, therefore, an object of this invention to provide a control system for an automated manufacturing facility that enables ready modification of input and output signals transferred between a master control computer and the facility's processing components. The system should provide increased standardization and adaptability to the specific requirements of end-users. The systems should employ standardized control links and be adaptable to utilize known, widely available communication protocols to deliver data. The system should also enable the use of less manufacturing floor space through the thoughtful placement of hardware and the reduced need for dispersed hardware.